1. Field of the Invention
The present invention relates to a pillar garnish disposed in a vehicle having a curtain side air bag apparatus, more particularly, to a pillar garnish provided with a guide surface that is formed integrally with the pillar garnish in the upper part of the pillar garnish, wherein the guide surface guides the direction in which an inflating air bag unfolds.
2. Description of the Related Art
A curtain side air bag apparatus is disposed above a pillar garnish in order to protect the passenger's head in case of a vehicle accident. A pair of the curtain side air bag apparatuses is disposed in a folded manner in the vicinity of both left and right edges of the roof trim and are unfolded downwards like curtains. The roof trim is made of an interior material that extends from above front pillars (A pillars) to the rear part of the interior of the vehicle beyond center pillars (B-pillars) and covers the roof panel of the vehicle. When the curtain side air bag apparatus is subjected to an impact load, the air bag in the folded state is inflated and unfolds downwards due to inflation gas that flows into the air bag, then the air bag opens the side edge of the roof trim so that the apparatus is unfolded like a curtain between the pillar garnish and the passenger in the interior of the vehicle.
Since the air bag is unfolded downwards from above the pillar garnish (unfolded in the longitudinal direction of the pillar garnish) to come into contact with the upper end of the pillar garnish, it is necessary to prevent the air bag from becoming caught between the pillar garnish and a pillar panel when the air bag is unfolded. There is known a pillar garnish that is provided with a guide surface for this purpose. The guide surface, which is formed integrally with and at the top of the pillar garnish, controls the direction in which the air bag unfolds so that the air bag is appropriately unfolded inward in the interior of the vehicle.
The pillar garnish having an integrally formed guide surface mentioned above is disclosed, for example, in JP3125729B, JP4590804B and JP4211825B. The pillar garnish having the guide surface guides the air bag so that it is unfolded inwards in the interior of the vehicle by means of the guide surface when the curtain air bag is unfolded. Such a pillar garnish reduces the possibility that the pillar garnish may become disengaged and scattered by the air bag that is caught by the upper end of the pillar garnish and reduces the possibility that damage will be caused to the passenger. Furthermore, the air bag is prevented from being unfolded between the pillar garnish and the pillar trim, and accordingly the pillar garnish is prevented from being sandwiched by the passenger and the air bag. Thus, the passenger protection function of the air bag can be appropriately ensured.
Although the guide surface brings about the above-mentioned advantage, the pillar garnish must be sufficiently stiff in the vertical direction in order to enhance the guiding function of the air bag when it is unfolded. On the other hand, when the impact load is not large enough to cause the curtain air bag to open, the passenger's head may move in the width direction of the vehicle, i.e., the direction that crosses the direction in which the air bag unfolds, and may collide against the pillar garnish. Even when the curtain air bag opens, the passenger's head may collide against the pillar garnish before the curtain air bag opens. Such events may increase the value of Head Injury Criterion (HIC). In case in which the passenger's head directly collides with the pillar garnish, a pillar garnish that is less stiff, and that therefore will more easily buckle or more easily become deformed, will provide better impact absorption characteristics for the passenger's head.
It is an object of the present invention to provide a pillar garnish that has higher stiffness in the vertical direction and limited stiffness in the width direction of a vehicle, i.e., the direction that crosses the vertical direction.